Typically, a telephoto lens is composed of two lens groups spaced at some interval, the front lens group having a strong positive lens power and the rear lens group having a strong negative lens power. The greater the distance between the lens groups and the greater the absolute values of the lens power of the two lens groups, the smaller the telephoto ratio will become. However, various aberrations such as transverse chromatic aberration, curvature of the image field and distortion are increased disadvantageously.